Numerous liquid bleaching compositions containing hypochlorite are well-known in the art. They have been extensively described to help with the removal of “problem” stains, such as coffee, tea, grass and red wines that are very difficult to remove from garments by ordinary washing, either by hand or with the use of a washing machine.
However, hypochlorite-containing bleaching compositions may cause yellowing and damage to fabrics being washed. Also, such compositions may cause corrosion to metallic decorations on the garments, such as buttons, buckles, etc. These compositions also may cause damage to the stainless steel or other metallic parts of washing machines, especially when the compositions are used in pre-treatment applications under stressed condition, for example, during soaking of garments for extended periods of time using the drum of the washing machines, or when applied onto the garments and left to act on the garments for an extended time period before washing of the garments.
In one aspect of the present invention, there is provided a hypochlorite-containing bleaching composition suitable for laundry application that enhances fabric whiteness.
In a further aspect of the present invention, there is provided a hypochlorite-containing bleaching composition suitable for laundry application that reduces fabric damage caused by conventional hypochlorite compositions.
In yet a further aspect of the present invention, a hypochlorite-containing bleaching composition is provided that is suitable for laundry application wherein the composition provides protection to stainless steel and other metallic parts of washing machines, as well as to metallic garment decors.
U.S. Pat. No. 6,946,435 B1 discloses a bleaching composition comprising hypochlorite and increased sodium hydroxide to remove menstrual fluid, underarm perspiration or hard-to-remove stains.
U.S. Pat. No. 7,109,157 B2 discloses a bleaching composition the same as the above but with added reduced damage to the fabric benefit when compared with popular chlorine bleaches.
U.S. Pat. No. 6,090,770 discloses a bleaching composition containing hypochlorite, alkali hydroxide, silicate and phosphoric and/or phosphonate to protect the textiles treated against encrustation and yellowing, even in the presence of water hardness and heavy metal ions.
U.S. Pat. No. 5,746,936 discloses a bleaching composition comprising hypochlorite, metal carbonate, metal hydroxide and alkali metal phosphate to enhance fabric whitening and/or provide safety benefits.
U.S. Pat. No. 6,153,120 discloses a bleaching composition containing hypochlorite, hydroxide, carbonate, silicates, borate and mixtures thereof and a polymer to prevent the precipitation of the buffering salt to improve fabric whiteness and safety.
U.S. Pat. No. 5,130,043 discloses thickened aqueous automatic dishwashing detergent compositions of which silicate is present at 4% to 10%, polycarboxylate polymers and phosphate esters having enhanced stability and cohesiveness.
U.S. Pat. No. 4,741,858 discloses time-release bleaching compounds containing sodium-silicate coated hypochlorite to reduce fabric and dye damage in fabric bleaching while facilitating the inclusion of optical laundry additives such as enzymes and brighteners.
U.S. Pat. No. 5,567,247 discloses a concentrated cleaning composition for cleaning outdoor surfaces containing chlorinated bleach solution, surfactant, phosphate and silicate.
U.S. Pat. No. 5,843,190 discloses an aqueous liquid bleaching composition having improved whitening and fabric safety performance consisting of an alkali metal hypochlorite, an alkali metal silicate, a strong source of alkalinity and an alkali metal carbonate. U.S. Pat. No. 5,843,191 discloses a similar composition except that the level of hypochlorite is from 0.0015% to 0.5% by weight.
U.S. Pat. No. 5,236,614 discloses a stable microemulsion detergent composition that includes hypochlorite, higher alcohol sulfate, higher paraffin sulfonate detergents, higher fatty acid soap, alkali metal hydroxide, perfume, branched lower alcohol co-surfactant and periodate.
While several hypochlorite-containing bleaching compositions have been described in the prior art for laundry applications, the advantage with the use of silicate and periodate to provide enhanced fabric and equipment safety have not been recognized until now.